Pipe part with a widened end

ABSTRACT

A plastic pipe end or socket provided with a circuumferential groove, the bottom of the groove being provided with a circumferential recess on the outer side and a corresponding heightening on the inner side of the bottom. The most inwardly situated upstanding wall of the recess merges substantially abruptly with said bottom.

- United States Patent O0stenbrink June 3, 1975 PIPE PART WITH A WIDENED END 2,991,092 7/1961 MacKay 285/231 x 4 1751 n n r: l r n h y Onsienbriuk, 55392;; 3534 350;??? iii/332i Hardenberg, Netherlands REIGN P OR AP NS F0 ATENTS PLICATIO [73] Asslgnee Zwone" Netherlands 207,372 11/1923 United Kingdom 285/231 [22] Filed: June 29, 1973 798,430 3/1936 France 285/231 x [21] Appl' 375154 Primary ExaminerWerner H. Schroeder Assistant Examiner-Peter Nerbun [30] Foreign Application Priority Data Attorney, Agent, or FirmWilkinson, Mawhinney &

June 30, 1972 Netherlands 7209102 Theibault [52] US. Cl. 264/94; 264/296; 285/231; [57] ABSTRACT 285/1 10 A plastic pipe end or socket provided with a circuumlift. Cl. ferential g the bottom of the groove being p Fleld of Search vided a circumferential. recess on the Outer Side 277/DIG. 2; 264/94, 296, 9 99 and a corresponding heightening on the inner side of R f Ct d the bottom,

e erences I e The most inwardly situated upstanding wall of the UNITED STATES PATENTS recess merges substantially abruptly with said bottom. 1,747,942 2/1930 Lanninger 285/231 2,953,398 9/1960 Haugen et al 285/231 X 1 Claim, 3 Drawmg Flgures PIPE PART WITH A WIDENED END DISCLOSURE OF THE PRIOR ART My invention relates to a plastic pipe part with a widened end in which is formed a circular groove-shaped chamber which is delimited by two side walls of the groove and the bottom thereof.

Such pipe parts with widened ends are known. They have, however, the drawback that the bottom of the groove merges fluently with the innermost lateral wall of the groove-shaped chamber, while in order to allow a sealing ring, with skirt protruding from the grooveshaped chamber, to be well retained in the grooveshaped chamber it is desirable that the bottom merges abruptly with the wall.

SUMMARY OF THE INVENTION It is an object of my invention to obviate these difficulties by the arrangement that the bottom of the groove on its inner side is provided with a circular raised bottom part extending all round and formed between the side walls of the groove, while the bottom of the groove merges abruptly with the innermost lateral wall of the groove.

Such an abrupt transition from bottom to side wall can namely only be obtained by providing an annular raised part in the central part of the recess in which the groove-shaped chamber is formed, whereby the plastic material is just driven to the corners to thereby ensure an abrupt transition.

In front of the raised part of the groove bottom a pocket is advantageously formed in the groove bottom on the outer side thereof.

My invention relates likewise to a method for manufacturing a pipe part with widened end, in which is a circular groove-shaped chamber, by deforming a pipe part owing to inner overpressure and surrounding the deformed pipe part by a die with at least one recess with a substantially rectangular recess and related to the groove-shaped chamber to be formed.

Such a method is known per se but has the drawback that no abrupt transition from the groove bottom to be formed to the most inwards situated side wall can be obtained.

It is therefore an object of my invention to obviate these difficulties by the arrangement that between the lateral walls delimiting the recess the bottom of the recess is provided with a circular raised part.

The circular raised part merges advantageously by rounded sides with the bottom of the recess.

My invention also relates to a formed pipe part obtained while performing the method according to the invention.

SURVEY OF THE DRAWINGS FIG. 1 shows a section through a pipe connection obtained by using a pipe part according to the invention;

FIG. 2 shows a section through a die with a plastic pipe heated by blowing, which has adapted itself to the shape of the die, and

FIG. 3 shows a muff for connecting tube ends.

DESCRIPTION OF A PREFERRED EMBODIMENT:

In the FIGURE a pipe part is denoted by l with a widened end 2 in which is a circular groove-shaped chamber 3, the chamber being delimited by two lateral walls 4 and 5 and a bottom of the groove.

In the groove-shaped chamber 3 is a sealing ring 7 to which is connected a sealing skirt 8 which penetrates into the recess 2 when a male pipe part 9 is slid into the pipe part 1. The skirt 8 is provided with protrusions 8a which ensure a proper sealing between the widened part 2 and the penetrating pipe part 9.

In order to retain the ring 7 there is provided a lock ring 10 with a substantially hoof-shaped cross-section the widest part of which cooperates with the wall 5 of the groove-shaped chamber 3.

It should be noted that the wall ends in an end part 11 the smallest diameter of which is smaller than the diameter of the widened part 2 of the pipe.

The ring 7 is formed in such a way that it contacts the lateral wall 4 of the groove-shaped chamber and the bottom 6 of the groove-shaped chamber, but on the other hand there rests a particular space between the wall 5 of the groove-shaped chamber 3 and the lateral wall 12 of the rubber ring 7.

In the known pipe connections in which such a pipe part with widened end and a groove-shaped chamber 3 is used the junction between the bottom 6 of the groove and the innermost side wall 4 of the groove-shaped chamber is rather rounded, so that at the location of the angular point 13 there is a rounded junction. This rounded junction has a drawback since it is possible that hereby the ring 7 is slightly pulled outwards on inserting the penetrating pipe part 9 when the latter comes into contact with the skirt 8 and the protrusions 8a.

It is an object of my invention to obviate these difficulties by providing the bottom of the groove on its inner side with a circular raised portion 14, between the side walls 4 and 5 of the groove, while the bottom of the groove merges abruptly at 13 with the innermost lateral side wall 4 of the groove.

In order to obtain this circular raised part of the bottom of the groove one proceeds as follows when a thermoplastic pipe part 1 is deformed by means of a die 16. This die 16 is provided with a recess 17 into which the plastic material of the pipe part 1 is pressed by blowing due to internal overpressure of air or another gas until the plastics has for the greater part contacted the inner wall of the recess 17. It is, however, very difficult to arrange that the plastic at the location of the point 13 contacts the junction 18 which would-be very desirable to obtain an abrupt transition from the bottom 6 of the groove to the lateral wall 4.

In order to obtain this abrupt transition at the location whereat the bottom 6 merges with the side wall 4 the bottom of the recess 17 is provided with a circular raised part 15, whereby when plastic material in heatdeformable condition is pressed, e.g., at a temperature ranging from to for polyvinylchloride, the synthetic material starts flowing in the direction of the junction 18 and as a consequence an abrupt transition is achieved.

It is obvious that due to the rounded junctions of the groove-shaped raised part 15 a pocket, which is likewise circular and denoted by 19, is formed on the outer side of the groove-shaped chamber 3.

FIG. 3 shows a muff for connecting two pipe ends.

The female ends 22 and 23 of the muff are separated by a collar 20 which may also be formed by a blowing technique. The other parts are indicated by the same numerals as used in FIG. 1.

groove-shaped chamber, comprising deforming a pipe part by introducing internal overpressure and surrounding the pipe part to be deformed by a die with at least one recess, forming the groove-shaped chamber deformed with a substantially rectangular crosssection, defining a recess in said pipe part, the bottom of which is provided with a circular raised part extending all round. and forming an all round extending raised part merging by rounded sides with the bottom of the recess. 

1. A method for manufacturing a plastic pipe part with widened end, in which is provided a circular groove-shaped chamber, comprising deforming a pipe part by introducing internal overpressure and surrounding the pipe part to be deforMed by a die with at least one recess, forming the groove-shaped chamber deformed with a substantially rectangular cross-section, defining a recess in said pipe part, the bottom of which is provided with a circular raised part extending all round, and forming an all round extending raised part merging by rounded sides with the bottom of the recess. 